JOHN Collins, the Celtic assistant manager, has warned the Scottish champions won’t be able to compete at the highest level in Europe again unless they abandon their prudent business plan.

Collins will leave Parkhead along with manager Ronny Deila after Celtic are presented with the Ladbrokes Premiership trophy following their final league game with Motherwell on Sunday.

The former Monaco midfielder was unable to help the Glasgow club qualify for the group stages of the Champions League during his two years on the backroom staff - much to the disappointment of their supporters.

However, he believes delivering success in Europe is now far more demanding for Celtic than it was 10 years ago due to the huge sums of money clubs in other countries make from television broadcasting deals.

The former Scotland internationalist reckons the only way for them to compete at that level in the future would be by greatly increasing the amount of money they spend on players – or by developing their own stars.

“Martin O’Neill was signing English Premier League players when he was manager – Celtic will never be able to sign an English Premier League player,” said Collins. “They can’t compete on salaries. That’s a fact.

“Fans still look back on those days and think ‘we want that again’, but it’s very difficult. It will stay that way unless the club breaks the wage structure by four or five times the current rate.

“We are shopping in different places. You have to be very creative in your scouting and development and create more of our own young players. That’s the hope for the future because we cannot buy the finished product for this club.

“We buy young and unproven talents and hope we can develop them under tremendous levels of expectation of having to win every week. Ronny has said that it’s difficult and not an easy place for youngsters to come and develop.”

Collins added: “Then once you develop them and polish them up someone comes to buy them as they have much more money than us. That’s the reality – clubs have the funds and we don’t have.

“It’s disappointing, but the word is reality. It’s the financial reality and a lot of people forget that we have restraints on salary and fees. I’m not crying about it – we knew it and the next manager will know it as well.

“Big clubs have got the big finances because of TV money. It’s not about crowds as Rangers and Celtic have crowds as big as anyone. We are a small country and we will never get the money they have. The days of competing with them are gone.

“The only thing we can hope for is that we produce four or five through the academy into the first team. That’s the only hope of being able to sustain it and get up there.”

Collins, who has managed at Hibs and Charleroi in Belgium and spent a stint as a director of football at Livingston, admitted he was keen to return to the game in some capacity when he leaves Celtic.

“If the right offer comes along,” he said. “I have had the benefit now of being in different positions. I have been a manager, a director of football and a coach. I have also been a television pundit for many years. I have seen it from all angles now. I have more experience in different positions. I think going forward I will either be a director of football or a manager again.

“We will see what the future holds, but I am not against going abroad. I have gone abroad before as a manager and as a player."